1. Field of the Invention
The present invention relates to an electronic zoom function of extracting a part of an object image formed by an image sensor and displaying or recording it on a recording medium.
2. Description of the Related Art
There has conventionally been known an image capturing apparatus having a so-called electronic zoom function of extracting a part of an object image formed by an image sensor and displaying or recording it on a recording medium.
Japanese Patent Laid-Open No. 2001-078081 discloses a known image capturing apparatus having such an electronic zoom function.
The image capturing apparatus disclosed in Japanese Patent Laid-Open No. 2001-078081 comprises a first reading means for adding n (n: natural number) pixels for pixels in a first imaging area 201 and reading out the resultant pixels. This apparatus also comprises a second reading means for not adding or adding m (m<n; m: natural number) pixels for pixels in a second imaging area 202 narrower than the first imaging area 201 and reading out the resultant pixels. This arrangement allows display that does not make the photographer uncomfortable by setting the same resolution in enlarged display and normal display on a display means.
Unfortunately, the above-described conventional technique merely maintains the display quality constant by adding n pixels in a wide display range and not adding or adding m pixels fewer than n pixels in a narrow display range. That is, since this technique does not take the object illuminance into consideration in adding pixels, the relationship between the electronic zoom magnification and the number of added pixels corresponding to the object illuminance still remains to be improved. That is, as the object illuminance decreases and the number of added pixels increases, the resolution of an image lowers if the electronic zoom magnification is raised carelessly.